FRI0249 Long-term safety and efficacy of treatment with subcutaneous abatacept in japanese patients with ra who were mtx inadequate responders – 76-week results

Immunogenicity of anti-TNF biologic agents in the treatment of rheumatoid arthritis

INTRODUCTION

The use of biologic disease-modifying anti-rheumatic drugs (DMARDs), including therapeutic antibodies, antibody fragments and protein constructs that target key mediators in the pathophysiology of rheumatoid arthritis (RA), has improved the chance of achieving low disease activity and clinical remission. However, individual patients respond differently to biologic DMARD therapy, particularly the tumor necrosis factor (TNF) inhibitors.

AREAS COVERED

While the variation of clinical response may be related to pharmacogenetic and other unknown factors, immunogenicity associated with some of these agents may contribute in part to a lack of efficacy and immune-mediated side effects. Timely detection of immunogenicity may avoid continued administration of ineffective treatment, and reduce unnecessary risks and costs. Access to and appropriate implementation of clinically validated drug level assays is required.

EXPERT OPINION

There are currently no evidence-based recommendations to guide biologic therapy on the basis of drug level and immunogenicity testing but as more data become available and better tests are developed, a strategy of immunopharmacologic guidance to individualize treatment of RA will emerge. The potential benefits of this approach must be balanced against the costs of monitoring, and further research is required.

Efficacy, safety, pharmacokinetics and immunogenicity of abatacept administered subcutaneously or intravenously in Japanese patients with rheumatoid arthritis and inadequate response to methotrexate: a Phase II/III, randomized study

OBJECTIVE

To evaluate efficacy and safety of subcutaneous (SC) and intravenous (IV) abatacept and background methotrexate (MTX) in Japanese patients with rheumatoid arthritis (RA) and inadequate response to MTX (MTX-IR).

METHODS

Double-dummy, double-blind study (NCT01001832); 118 adults with ≥ 10 swollen joints, ≥ 12 tender joints and C-reactive protein (CRP) ≥ 0.8 mg/dL randomized 1:1 to SC abatacept (125 mg weekly) with IV loading (∼10 mg/kg on Day 1), or IV abatacept (∼10 mg/kg monthly) for 169 days, both also receiving MTX (6-8 mg/week). Primary endpoint was Day 169 American College of Rheumatology (ACR)20 response; other efficacy endpoints, safety and immunogenicity were assessed.

RESULTS

Similar proportions of patients achieved ACR20 responses at Day 169 with SC (91.5% [95% CI 81.3, 97.2]) and IV abatacept (83.1% [71.0, 91.6]). ACR50/70 responses, adjusted mean changes from baseline in Health Assessment Questionnaire-Disability Index scores and remission rates (28-joint Disease Activity Score [CRP] < 2.6) were also comparable between groups. Serious adverse event frequencies (5.1% vs. 3.4%) were similar with both formulations. One patient per group tested seropositive for immunogenicity. Weekly SC abatacept dosing achieved mean serum concentrations > 10 μg/mL (minimum therapeutic target).

CONCLUSIONS

SC abatacept demonstrated comparable efficacy and safety to IV abatacept, with low immunogenicity rates, in MTX-IR Japanese patients with RA.